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Richard Dawkins has an excellent summary of the idea of evolution in this week's New Scientist, in an article titled "The world's ten biggest ideas". Here it is—it's a very clear, short, six paragraph explanation of a big idea, fewer than 600 words. Now if only everyone could just understand this:

The world is divided into things that look designed (like birds and airliners) and things that don't (rocks and mountains). Things that look designed are divided into those that really are designed (submarines and tin openers) and those that aren't (sharks and hedgehogs). The diagnostic of things that look (or are) designed is that their parts are assembled in ways that are statistically improbable in a functional direction. They do something well: for instance, fly.

Darwinian natural selection can produce an uncanny illusion of design. An engineer would be hard put to decide whether a bird or a plane was the more aerodynamically elegant.

So powerful is the illusion of design, it took humanity until the mid-19th century to realise that it is an illusion. In 1859, Charles Darwin announced one of the greatest ideas ever to occur to a human mind: cumulative evolution by natural selection. Living complexity is indeed orders of magnitude too improbable to have come about by chance. But only if we assume that all the luck has to come in one fell swoop. When cascades of small chance steps accumulate, you can reach prodigious heights of adaptive complexity. That cumulative build-up is evolution. Its guiding force is natural selection.

Every living creature has ancestors, but only a fraction have descendants. All inherit the genes of an unbroken sequence of successful ancestors, none of whom died young and none of whom failed to reproduce. Genes that program embryos to develop into adults who can successfully reproduce automatically survive in the gene pool, at the expense of genes that fail. This is natural selection at the gene level, and we notice its consequences at the organism level. There has to be an ultimate source of new genetic variation, and it is mutation. Copies of newly mutated genes are reshuffled through the gene pool by sexual reproduction, and selection removes them from the pool in a way that is non-random.

What makes for success in the business of life varies from species to species. Some swim, some walk, some fly, some climb, some root themselves into the soil and tilt green solar panels toward the sun. All this diversity stems from successive branchings, starting from a single bacterium-like ancestor, which lived between 3 and 4 billion years ago. Each branching event is called a speciation: a breeding population splits into two, and they go their separately evolving ways. Among sexually reproducing species, speciation is said to have occurred when the two gene pools have separated so far that they can no longer interbreed. Speciation begins by accident. When separation has reached the stage where there is no interbreeding even without a geographical barrier, we have the origin of a new species.

Natural selection is quintessentially non-random, yet it is lamentably often miscalled random. This one mistake underlies much of the sceptical backlash against evolution. Chance cannot explain life. Design is as bad an explanation as chance because it raises bigger questions than it answers. Evolution by natural selection is the only workable theory ever proposed that is capable of explaining life, and it does so brilliantly.

"...the religious memes that include the notion of hell... These visions of horror work wonders. Terrified humans by the score allow unprovable concepts to take up residence in their skulls."

Over the past week I was constantly reminded of these words by Howard Bloom in his fascinating book The Lucifer Principle - A Scientific Expedition Into the Forces of History.

Bloom's argument is applicable to some readers whose reaction to my column (The Earth is not 6 000 yrs old!), explaining the techniques scientists apply to determine the age of the Universe or Earth and everything on it, was one of what I can only call terrified and total negation about the findings of science.

But how do scientists explain the psychological hold religion has on gullible people's lives?

In 1976 Richard Dawkins published The Selfish Gene, a book that was later described as one of the 100 best books of the past century.

In it he took the evolutionary process of variation, natural selection and genetic heredity a step further by applying it to human cultural transmission.

He called this new replicator of cultural imitation and copying the meme.

"Genes are replicated, copied from parent to offspring down the generations," he wrote in a later book, Unweaving the Rainbow - Science, Delusion, and the Appetite for Wonder. "A meme is, by analogy, anything that replicates itself from brain to brain, via any available means of copying."

The Meme Machine

According to Dawkins, a theory later expanded by scientists such as Susan Blackmore in her insightful book The Meme Machine, Richard Brodie in Virus of the Mind - The New Science of the Meme, and Aaron Lynch in Thought Contagion - How Belief Spreads Through Society, "memes can be good ideas, good tunes, good poems, as well as drivelling mantras. Anything that spreads by imitation, as genes spread by bodily reproduction or by viral infection, is a meme."

Religion is a mental virus and one of the strongest memes transmitted from parents to vulnerable children who do not really have any choice in whether their minds should be allowed to be exposed to this virus. (Dawkins talks about the brains of children as "those mental caterpillars").

Blackmore points out that genes build the hardware (the physical bodies of people), but that memes are the software and that this co-evolution may have driven the inflation of the human brain.

Why is it so difficult for religious people to accept a scientific fact such as evolution, despite all the evidence proving its validity in biological development?

I am regularly bombarded by readers denying any truth in evolution and sending me long quotations from creationist websites that distort the words of scientists, and bluntly, without any shame or qualms, mislead their readers about what Darwin and modern evolutionary biologists indeed say about evolution.

The Selfish Gene

In The Selfish Gene Dawkins explains this phenomenon of denial and deceit: "The survival value of the god meme in the meme pool results from its great psychological appeal.

It provides a superficially plausible answer to deep and troubling questions about existence. It suggests that injustices in this world may be rectified in the next.

The 'everlasting arms' hold out a cushion against our inadequacies which, like a doctor's placebo, is none the less effective for being imaginary.

These are some of the reasons why the idea of God is copied so readily by successive generations of brains. God exists, if only in the form of a meme with high survival value, or infective power, in the environment provided by human culture."

According to Bloom the original religious meme of the Old Testament seldom leapt from one gene pool to another.

The ancient Hebrews made no effort to convert the heathens. "Unbelievers weren't family. If the meme was to retain its role as a genetic marker, only those who shared the same genes could share the same god. That was the tribal concept, held by primitive peoples the world over."

The apostles changed all that. Paul was one of the early innovators of a new concept: transferable religion, says Bloom, and emphasises that like Buddha, Paul freed gods from chromosomal components. "Thanks to Paul, the Christian meme would eventually sweep together an awesome jumble of genes."

As the virus of the mind spread, Paul and his followers, also later the prophet Mohamed, "helped make the meme the world's most powerful form of replicator", a meme that is so strong that even the factual onslaught of scientific facts from Darwin to modern times that contradict the meme's claims, face an upward struggle.

Still, science progresses relentlessly, even if the noise of unscientific prophets and contortionists tries to drown its factual, testable and verifiable findings through misleading distortions of and lies about the very same science.

George Claassen is the science editor of Die Burger, Cape Town's largest circulation daily newspaper.